This invention relates to tubing hanger seals; more particularly this invention relates to tubing hanger seals that utilize a drive sleeve to compress a metal to metal seal between the inside of a tubing head and the outside of a tubing hanger.
In oil field or natural gas production operations it is always essential to seal the annulus between the production tubing and the well casing. In high temperature environments, metal seal rings have been used in place of elastomeric or plastic seals. In most cases, the tubing string provided the weight to compress the metal seal between the hanger and the tubing head shoulder. The result was that seal integrity was determined by an ever changing tubing string weight and annular formation pressure against the projected surface area of the bottom of the hanger. In addition, the seal was uni-directional and offered little protection against a blowout situation.
It is therefore an object of this invention to provide a metal to metal tubing hanger seal that does not depend on the weight of the tubing string for its integrity.
It is a further object of this invention to provide a metal to metal seal that can be energized to a given load unaffected by the tubing string.
It is yet a further object of this invention to provide a metal to metal seal that will retain its integrity against upward as well as downward forces.